HOFFMAN!!! This guy is so versatile and you get a sense of this just from looking at the list of films he's been in. Even when he plays a minor character he stands out! Other great PHS moments: "Doubt," "The Big Lebowski," "Scent of A Woman," and "Cold Mountain."

Wow... that's tough. Again, I love both men. I'd probably say Giamatti because he's funnier. I've seen him in more comedies where he really stands out. I like PSH and I've yet to see him do a bad performance.

They're both in my list of the best actors of the past decade. Hoffman as Lester Bangs in Almost Famous and Giamatti as Harvey Pekar in American Splendor. Those are two iconic performances.

@Jack – Hoffman has had the better films overall but I think Giamatti has been fairly consistent over the years. Giamatti just needs that one big crossover flick (i.e. his own Capote type film) to get more leading man roles.

@Andrew – Cinderella Man is a lot like A Beautiful Mind more for me. Loved it when I saw it in the theatres but it loses its appeal the more I re-watch it. I think it is just something about Ron Howard films in general that have that result on me.

@Larry – Giamatti did take a bit of a dip around the Shoot Em’ Up time but, judging by the reviews of Win Win and Barney’s Version, he seems to be getting back on track.

@Rachel – Hoffman was good in the films you mentioned, though I see Doubt as being a major role instead of a minor one. Regardless, you make a good point.

@Jess – I had a feeling Hoffman would get the most love.

@thevoid - Giamatti has definitely had the comedic edge over Hoffman. I thought he absolutely killed it in Private Parts. Both actors would easily make my list of top character actors of this generation. They can handle both the small rolls and the major ones with ease.

@Castor – I have to agree with you on Giamatti being more of the everyman type of actor. Hoffman is great, but cannot pull off the “average Joe” quiet as well as Giamatti can.

@Fletch - Funny I thought Happiness would be the deal closer for most people. Though it seems to have gone unnoticed in the debate. It has been years since I saw Scent of a Woman, I cannot even remember Hoffman's role in the film.

Bear in mind, I'm 90% joking about Scent of a Woman. He has a pretty small role, but it was where I first noticed him, and he's pretty funny in it (and it's pretty funny to see him so young playing a high schooler).

I don't think enough people have seen Happiness to make that big of an impact.

Hoffman all the way. I've yet to review one of his movies, but he's a fairly versatile actor. He makes a big impression, but doesn't have to "act big" to do it.Giamatti is good, but a lot of his roles can feel very similar. When he gets "shouty," his roles just blend for me...

@Thaddeus - You make a good point in regards to Hoffman making a big impression but not having to "act big" to do it. I find that too many actors feel that the only way to make a mark is to play the role bigger than they really need to.